Question about 1998 GMC Jimmy

1 Answer

1998 GMC Jimmy SLT warm air only from heating ducts

When the vehicle is fully warmed up (coolant temp about 200Fper vehicle gauge) the air temperature from all the ducts is only warn...not hot. I have replaced the stat even thought the temp gauge indicate normal operating temperature. I have removed the the lines from the heater core and back flushed the heater core.I had very good flow throught the core. The inlet line to the core is very hot to the touch and the out let line is warn so it seem like the system is exchanging heat. All the air positions fubction properly. By this I mean in floor mode you only get air fron the floor duct. In I/P (instrument pannel) mode it blows from the I/p only and in defrost mode it only blows on the windshield.
Thanks for you time.

Posted by on

  • Anonymous Mar 18, 2014

    replace thermotrat, heater core

×

1 Answer

  • Level 3:

    An expert who has achieved level 3 by getting 1000 points

    All-Star:

    An expert that got 10 achievements.

    MVP:

    An expert that got 5 achievements.

    Guru:

    An expert who has written 7 tips or uploaded 3 video tips

  • Master
  • 449 Answers

If you claim that your heater core is flushed properly then my bet is the temp regulator is bad.

Posted on Jan 13, 2009

Add Your Answer

Uploading: 0%

my-video-file.mp4

Complete. Click "Add" to insert your video. Add

×

Loading...
Loading...

Related Questions:

3 Answers

My 2000 jimmy has heat problems. the heat goes from cold to hot to warm to cold etc. what could the problem be?


If the temp gauge is now more stable, the problem is in your heater system, not the engine cooling system.

Sep 12, 2014 | 2000 GMC Jimmy

1 Answer

Heater issue


This sounds like a thermostat that is fully open all the time. It allows the engine coolant to warm when sitting still (no air being forced thru the radiator), but even that goes away when moving, since the air through the radiator will remove that heat from the coolant. Does you van have a temp gauge? Is so, at full operating temp. most vehicles have coolant temps of 180-195 degrees F, depending on the thermostat installed. Anything less indicates a thermostat that is starting to malfunction.

Dec 08, 2013 | 2000 Mercury Villager

2 Answers

Air pockets in radiator


Air can be purged. While your engine is cool remove radiator and reservoir caps. Place funnel in radiator. Turn heat to the highest position and start vehicle. Add coolant to radiator as needed while vehicle warms up. You should see bubbles coming out of radiator. Fill reservoir to between cold and hot fill lines. Replace caps when bubbling stops but before coolant temperature reaches normal operating temperature. Never remove the radiator cap until engine has fully cooled down.

Jan 15, 2013 | 2008 Nissan Frontier

1 Answer

1998 gmc surburban. front blows 82 degrees, rear blows 48 degrees. ambient is 91 degrees. this is with max-recirc-full tilt.the valve for the heater core does not change position no matter where i put the...


Hi John,
Your right with your diagnostics, you have a blend door problem. If your switching to cool air and it is still hot then you also have a heat exchange unit fault, this is the component that changes the water flow from hot to cool by shutting off. If it is not operating correctly this will give you constant hot air no matter where you temperature switch is positioned.
As for the warm air while the engine is cold, sounds like the blend door is still open to atmosphere tempreture and if it is hot outside will pull that hot air into the inside of the vehicle.
Have the heat exchange valve checked, and the only way the check blend door operation is to remove the wiring from the blend doors and have the circuit tested. If the circuit is ok then the blend doors will need to be replaced.
Hope this helps

Jul 24, 2011 | 1998 GMC Suburban

1 Answer

1998 Jimmy with electrical controls for temperature. Replaced Themostat, Flushed heater core, replaced damaged vacuum lines. Vehicle produces heat to heater core but only luke warm interior temp. Rotated...


Suggestion: see if the blend door opens or closes completely to allow all air through the heater core. To see the blend door moving, remove the panel that says "Cut here for service" under the hood along the firewall. I have a 99 Bravada where the blend door keeps moving back and forth constantly. Changed the blend door actuator but still keeps moving. The air inside is only warm since the door keeps allowing bypassed air through.

Jan 04, 2011 | 1998 GMC Jimmy

2 Answers

Engine temp


try skewing the engine coolant temperature sensor with a multi-meter and a temp vs resistance or voltage chart. the ect could be out of range and not set a code. also check actual engine temp with an infrared thermometer. hope this helps

Jan 26, 2010 | 1997 GMC Jimmy

1 Answer

I have a 1998 Dodge Durango SLT-V6 that has no heat.


The heater core might need back flushed, I just did mine this winter. Go to dakota-durango.com and introduce your self and your rare as ever truck, a v6 durango, and have fun.

Dec 21, 2009 | 1998 Dodge Durango

1 Answer

Heat only works when temp gets about 220, just change the thermostat, will low coolent be the issue


You should see heat well prior to this heat, is your coolant level exceeding low? I have seen situations where the coolant level is so low it will not get to the heater until it warms up (by warming up the coolant has expanded thus filling up the heating system more.
I hope this may have helped,
Tom

Oct 03, 2009 | 1998 GMC Jimmy

2 Answers

1998 Dodge Durango no heat when using heater.


BLEND DOOR STUCK OR BROKEN. NEEDS TO REMOVE DASH AND HEATER/EVAP CORE BOS TO REPAIR REPLACE.

Jan 08, 2009 | 1993 GMC Safari

2 Answers

Heating System


The Engine Coolant Temperature (ECT) sensor is mounted in the intake manifold and sends engine temperature information to the ECM. The ECM supplies 5 volts to the coolant temperature sensor circuit. The sensor is a thermistor which changes internal resistance as temperature changes. When the sensor is cold (internal resistance high), the ECM monitors a high signal voltage which it interprets as a cold engine. As the sensor warms (internal resistance low), the ECM monitors a low signal voltage which it interprets as warm engine.
0900c1528008f125.jpgFig. 1: View of the Engine Coolant Temperature (ECT) sensor 0900c1528008f126.jpgFig. 2: Engine Coolant Temperature (ECT) sensor locationTESTING
See Figures 3 and 4
  1. Remove the ECT sensor from the vehicle.
  2. Immerse the tip of the sensor in container of water.
  3. Connect a digital ohmmeter to the two terminals of the sensor.
  4. Using a calibrated thermometer, compare the resistance of the sensor to the temperature of the water. Refer to the engine coolant sensor temperature vs. resistance illustration.
  5. Repeat the test at two other temperature points, heating or cooling the water as necessary.
  6. If the sensor does not meet specification, it must be replaced.
0900c1528008f120.jpgFig. 3: Intake Air Temperature (IAT) and Engine Coolant Temperature (ECT) sensor wiring diagram 0900c1528008f095.jpgFig. 4: ECT sensor temperature vs. resistance values

Oct 01, 2008 | 1993 GMC Sierra

Not finding what you are looking for?
1998 GMC Jimmy Logo

647 people viewed this question

Ask a Question

Usually answered in minutes!

Top GMC Experts

yadayada
yadayada

Level 3 Expert

60960 Answers

Colin Stickland
Colin Stickland

Level 3 Expert

21949 Answers

Jeff Turcotte
Jeff Turcotte

Level 3 Expert

6812 Answers

Are you a GMC Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides

Loading...